The present invention relates to a network node for a network provided in a transport device or means, in particular in an aircraft, and to a network for a transport device or means, in particular for an aircraft, having one or more such network nodes.
Energy supply networks (also called on-board networks in the case of transport means) serve to supply electrical energy to electrical consumers (loads) in a transport means such as, for example, an aircraft, a ship, a bus or a train. Frequently, the totality of all electrical components in the transport means is referred to as an on-board network. The electrical components include, inter alia, the cabling, control devices, sensors, indicator elements (such as warning and control lights, displays), actuators (such as electric motors, lights and lighting systems), bus systems, energy storage devices (such as batteries and accumulators) and generators. Frequently, conventional on-board networks are constructed in a star configuration in transport means such as aircraft. This means that the energy generated by generators disposed in the transport means is fed into the on-board network of the transport means via one or more feed-in points. Usually, a plurality of lines (frequently referred to as supply lines or primary supply lines) lead from this feed-in point, or these feed-in points, to individual loads or load groups comprising a multiplicity of loads. Consequently, usually each load or each load group is supplied with electrical energy by its own supply line, which goes out from the feed-in point.
This means either that an individual device (load) is supplied by an associated supply line or that a device group (load group) comprising a plurality of individual devices is supplied by a supply line. The lines leading from the feed-in point to the individual devices or device groups are centrally fuse-protected, by suitable fuses, at the feed-in point. As a result, faults or failures such as, for example, overvoltages or malfunctions in the individual devices or cables can be fuse-protected in a reliable manner. Over-reach to other individual devices, device groups and the functions executed therein is prevented.
The loads can call for the required energy at any time through the existing wired connection to the feed-in point. Some loads, such as actuators, convert electronic signals into mechanical movement or other physical quantities over long periods of time, frequently even continuously. Actuators are to a certain extent almost permanently in use and, accordingly, also require continuous energy replenishment. Frequently, on the other hand, other loads are in use only for a very short period of time, for example while they execute a short control operation, and subsequently return to a sleep mode. When in the sleep mode, the load requires only very little energy. An example of such loads is that of sensor nodes, which are frequently organized into sensor networks in transport means, in order to poll their environment by means of sensors and to forward the information received. These sensor nodes are usually only in use for short periods of time, namely, whenever they perform a corresponding measuring operation and forward the measurement information.
In order to make on-board networks independent of cables, there was a concept to provide a sensor system that supplies itself with current. For each individual sensor provided in the sensor system, its own generator, e.g., a thermoelectric generator (also called a thermoelement) or a vibration energy collector generates current. These systems are frequently combined under the general term “energy harvesting”. These systems obtain energy at given times from sources such as ambient temperature, vibrations or air flows. As an alternative to such an energy collector, a battery allows electrical energy to be provided for a certain period of time.